integration.go

     1  // Copyright 2024 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package p
     6  
     7  // This type and the following one will share the same GC shape and size.
     8  type Pointery struct {
     9  	p *Pointery
    10  	x [1024]int
    11  }
    12  
    13  type Pointery2 struct {
    14  	p *Pointery2
    15  	x [1024]int
    16  }
    17  
    18  // This type and the following one will have the same size.
    19  type Vanilla struct {
    20  	np uintptr
    21  	x  [1024]int
    22  }
    23  
    24  type Vanilla2 struct {
    25  	np uintptr
    26  	x  [1023]int
    27  	y  int
    28  }
    29  
    30  type Single struct {
    31  	np uintptr
    32  	x  [1023]int
    33  }
    34  
    35  var G int
    36  
    37  //go:noinline
    38  func clobber() {
    39  	G++
    40  }
    41  
    42  func ABC(i, j int) int {
    43  	r := 0
    44  
    45  	// here v2 and v3 can be overlapped.
    46  	clobber()
    47  	if i < 101 {
    48  		var v2 Vanilla
    49  		v2.x[i] = j
    50  		r += v2.x[j]
    51  	}
    52  	if j != 303 {
    53  		var v3 Vanilla2
    54  		v3.x[i] = j
    55  		r += v3.x[j]
    56  	}
    57  	clobber()
    58  
    59  	// not an overlap candidate (only one var of this size).
    60  	var s Single
    61  	s.x[i] = j
    62  	r += s.x[j]
    63  
    64  	// Here p1 and p2 interfere, but p1 could be overlapped with xp3 + xp4.
    65  	var p1, p2 Pointery
    66  	p1.x[i] = j
    67  	r += p1.x[j]
    68  	p2.x[i] = j
    69  	r += p2.x[j]
    70  	if j != 505 {
    71  		var xp3 Pointery2
    72  		xp3.x[i] = j
    73  		r += xp3.x[j]
    74  	}
    75  
    76  	if i == j*2 {
    77  		// p2 live on this path
    78  		p2.x[i] += j
    79  		r += p2.x[j]
    80  	} else {
    81  		// p2 not live on this path
    82  		var xp4 Pointery2
    83  		xp4.x[i] = j
    84  		r += xp4.x[j]
    85  	}
    86  
    87  	return r + G
    88  }
    89
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